<!DOCTYPE html>
<html lang="zh-CN">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>欢迎登录</title>
    <style>
        * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
            font-family: 'Segoe UI', 'Microsoft YaHei', sans-serif;
        }

        body {
            background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
            height: 100vh;
            display: flex;
            justify-content: center;
            align-items: center;
            overflow: hidden;
        }

        .login-container {
            background-color: rgba(255, 255, 255, 0.95);
            border-radius: 15px;
            box-shadow: 0 15px 35px rgba(0, 0, 0, 0.2);
            width: 400px;
            padding: 40px;
            position: relative;
            overflow: hidden;
            animation: fadeIn 0.6s ease-out;
        }

        .login-container::before {
            content: '';
            position: absolute;
            top: -50%;
            left: -50%;
            width: 200%;
            height: 200%;
            background: linear-gradient(to bottom right, rgba(255,255,255,0.3), rgba(255,255,255,0));
            transform: rotate(30deg);
            z-index: 0;
        }

        .login-header {
            text-align: center;
            margin-bottom: 40px;
            position: relative;
            z-index: 1;
        }

        .login-header h1 {
            color: #333;
            font-size: 28px;
            font-weight: 600;
            margin-bottom: 10px;
        }

        .login-header p {
            color: #666;
            font-size: 14px;
        }

        .input-group {
            position: relative;
            margin-bottom: 25px;
            z-index: 1;
        }

        .input-group input {
            width: 100%;
            padding: 15px 20px;
            border: none;
            background-color: #f5f5f5;
            border-radius: 8px;
            font-size: 16px;
            transition: all 0.3s ease;
            border: 1px solid #eee;
        }

        .input-group input:focus {
            outline: none;
            border-color: #667eea;
            box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.2);
            background-color: white;
        }

        .input-group label {
            position: absolute;
            left: 20px;
            top: 15px;
            color: #999;
            font-size: 16px;
            transition: all 0.3s ease;
            pointer-events: none;
        }

        .input-group input:focus + label,
        .input-group input:valid + label {
            top: -10px;
            left: 10px;
            font-size: 12px;
            background-color: white;
            padding: 0 5px;
            color: #667eea;
        }

        .remember-forgot {
            display: flex;
            justify-content: space-between;
            align-items: center;
            margin-bottom: 25px;
            font-size: 14px;
        }

        .remember-me {
            display: flex;
            align-items: center;
        }

        .remember-me input {
            margin-right: 8px;
        }

        .forgot-password a {
            color: #667eea;
            text-decoration: none;
            transition: color 0.3s;
        }

        .forgot-password a:hover {
            color: #764ba2;
            text-decoration: underline;
        }

        .login-button {
            width: 100%;
            padding: 15px;
            background: linear-gradient(to right, #667eea, #764ba2);
            border: none;
            border-radius: 8px;
            color: white;
            font-size: 16px;
            font-weight: 600;
            cursor: pointer;
            transition: all 0.3s ease;
            box-shadow: 0 4px 15px rgba(102, 126, 234, 0.4);
        }

        .login-button:hover {
            transform: translateY(-2px);
            box-shadow: 0 6px 20px rgba(102, 126, 234, 0.6);
        }

        .login-button:active {
            transform: translateY(0);
        }

        .signup-link {
            text-align: center;
            margin-top: 25px;
            font-size: 14px;
            color: #666;
        }

        .signup-link a {
            color: #667eea;
            text-decoration: none;
            font-weight: 600;
            transition: color 0.3s;
        }

        .signup-link a:hover {
            color: #764ba2;
            text-decoration: underline;
        }

        .social-login {
            margin-top: 30px;
            text-align: center;
        }

        .social-login p {
            color: #999;
            font-size: 14px;
            margin-bottom: 15px;
            position: relative;
        }

        .social-login p::before,
        .social-login p::after {
            content: "";
            position: absolute;
            top: 50%;
            width: 30%;
            height: 1px;
            background-color: #eee;
        }

        .social-login p::before {
            left: 0;
        }

        .social-login p::after {
            right: 0;
        }

        .social-icons {
            display: flex;
            justify-content: center;
            gap: 15px;
        }

        .social-icon {
            width: 40px;
            height: 40px;
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
            color: white;
            font-size: 18px;
            cursor: pointer;
            transition: transform 0.3s;
        }

        .social-icon:hover {
            transform: translateY(-3px);
        }

        .facebook {
            background-color: #3b5998;
        }

        .twitter {
            background-color: #1da1f2;
        }

        .google {
            background-color: #db4437;
        }

        @keyframes fadeIn {
            from {
                opacity: 0;
                transform: translateY(20px);
            }
            to {
                opacity: 1;
                transform: translateY(0);
            }
        }

        @media (max-width: 480px) {
            .login-container {
                width: 90%;
                padding: 30px 20px;
            }
        }
    </style>
</head>
<body>
<div class="login-container">
    <div class="login-header">
        <h1>欢迎回来</h1>
        <p>请登录您的账户继续</p>
    </div>

    <form>
        <div class="input-group">
            <input type="text" id="username" required>
            <label for="username">用户名或邮箱</label>
        </div>

        <div class="input-group">
            <input type="password" id="password" required>
            <label for="password">密码</label>
        </div>

        <div class="remember-forgot">
            <div class="remember-me">
                <input type="checkbox" id="remember">
                <label for="remember">记住我</label>
            </div>
            <div class="forgot-password">
                <a href="#">忘记密码?</a>
            </div>
        </div>

        <button type="submit" class="login-button">登录</button>

        <div class="signup-link">
            还没有账户? <a href="#">立即注册</a>
        </div>

        <div class="social-login">
            <p>或通过以下方式登录</p>
            <div class="social-icons">
                <div class="social-icon facebook">
                    <i class="fab fa-facebook-f">f</i>
                </div>
                <div class="social-icon twitter">
                    <i class="fab fa-twitter">t</i>
                </div>
                <div class="social-icon google">
                    <i class="fab fa-google">G</i>
                </div>
            </div>
        </div>
    </form>
</div>
</body>
</html>